Test terminals are used to perform field tests of electrical apparatus. For example, test terminals are used to conduct dielectric tests of substation equipment, such as transformers and circuit breakers. Properly testing electrical apparatus extends the service life of the electrical apparatus and facilitates preventing apparatus failure, which results in expensive downtime, lost revenue and costly apparatus repair and replacement.
The test terminal is disposed in an electrical distribution/transmission system between a high voltage power bus and the electrical apparatus to be tested. In the closed position, the test terminal allows electrical power to be transferred from the power bus to the electrical apparatus. When the test terminal is in an open position, the electrical apparatus is electrically isolated from the power bus such that electrical tests of the electrical apparatus can be conducted.
However, to conduct a mechanical test of the electrical apparatus, such as time travel testing of circuit breakers, requires the test terminal to be in the closed position. Thus, the mechanical test is performed with the test terminal in the closed position and the electrical test is performed with the test terminal in the open position. Moving the test terminal between open and closed positions increases the time required to conduct the tests. Accordingly, a need exists for a test terminal that minimizes the time to conduct the electrical and mechanical field tests of electrical apparatus by conducting both tests with the test terminal in the open position.
Additionally, the test terminal needs to be in the closed position to protect the test terminal from possible damage resulting from the mechanical testing of the electrical apparatus, such as damage from shock or vibration. Accordingly, a need exists for a test terminal that substantially eliminates damage resulting from mechanical testing of electrical apparatus.
Furthermore, the mechanical test is performed with the test terminal in the closed position such that the electrical apparatus being tested is not electrically isolated, thereby posing dangerous testing conditions. Accordingly, a need exists for a test terminal in which the electrical apparatus being mechanically tested is electrically isolated from the power distribution/transmission system.
Thus, there is a continuing need to provide improved high voltage test terminals for field electrical and mechanical testing of electrical apparatus.